(1) Field of the Invention
The present invention relates to three-dimensional video reproduction apparatuses which superimpose a sub video on a main video that is a three-dimensional video (3D video).
(2) Description of the Related Art
Recent years have seen a rapid spread use of recording media such as Blu-ray discs for recording data obtained by digitally coding and multiplexing a main video signal corresponding to a three-dimensional video and a sub video signal such as subtitles.
A main video signal conforms to the 4:2:2 format as one of the chrominance formats defined by the CCIR (International Radio consultative Committee), and is composed of a luminance signal using 8 bits for each pixel and a chrominance signal Db/Cr using 8 bits for each of two pixels. On the other hand, a sub video signal conforms to the 4:2:2 format as another one of the chrominance formats, and is composed of a luminance signal using 8 bits for each pixel and chrominance data Cb/Cr using 8 bits for each pixel.
When superimposing a sub video signal on a main video signal and reproducing the resulting video signal, there is a need to match the chrominance formats thereof before the superimposition. For example, a main video signal is converted from the 4:2:2 format to the 4:4:4 format, and then a sub video signal is superimposed on the main signal having the 4:4:4 format. Alternatively, the chrominance format of a sub video signal is converted from the 4:4:4 format to the 4:2:2 format, and then the sub video signal is superimposed on the main signal having the 4:2:2 format.
There are some known techniques for suppressing occurrence of a color different from the original color at an edge portion of a sub video or another portion when superimposing a main video and a sub video and displaying the resulting video in this way (for example, see Patent Reference 1 (Japanese Unexamined Patent Application Publication No. 2007-134883)).